Centrifugal pump



Jan. 12, 1954 H. A. LOCKHART 2,665,640

CENTRIFUGAL PUMP Filed Jan. 5, 1950' Patented Jan. 12, 1954 CENTRIFUGAL PUMP Harold A. Lockhart, Des Plaines, Ill., assignor to Bell & Gossett Company, Morton Grove, 111., a corporation of Illinois Application January 5, 1950, Serial No. 136,879

8 Claims.

My invention relates to centrifugal pumps of the radial flow type and more particularly to certain improvements therein which reduce manufacturing costs and facilitate assembly and disassembly.

The impeller assembly in pumps of the high velocity type, especially in the smaller sizes, is so constructed that the pump casing frequently must be composed of at least two parts which are bolted together to surround the assembly. Such an arrangement materially increases manufacturing costs which are important items in the highly competitive, small pump market.

It is therefore one object of my invention to devise a centrifugal pump in which the impeller assembly is arranged for endwise, axial mounting in operable relation to the volute of the pump casing that is cast in one piece.

A further object is to provide a pump of the character indicated in which the impeller assembly has a tight rim seal with the volute of the casing and a measure of looseness around the eye of the pump to prevent excessive return of the pumped liquid from the high to the low side of the pump externally of the outer shroud ring of the impeller.

These and further objects of the invention will be set forth in the following specification, reference being had to the accompanying drawing, and the novel means by which said objects are effectuated will be definitely pointed out in the.

claims.

The drawing is an elevation, partly in section, of the pump.

Referring to the drawing, the numeral I desighates a centrifugal pump casing having an inlet II and an outlet I2 which are connected by the usual volute chamber |3. Coaxial with the charm ber I3 is an impeller shaft I4 that is journaled in a bracket I5 attached to the casing If! by studs IS. The shaft I4 may be driven in any approved manner, such as by a motor (not shown).

The hub ll of an impeller I8 is keyed to the shaft I4 in symmetrical relation to the chamber I3 and a spring actuated seal assembly I9 encircles the shaft between the hub and an adjacent wall forming part of the bracket I5. The impeller I8 includes inner shroud rings 2| and 22 whose inner peripheries are connected to the en% of the huh I! and Whose outer peripheries abut with their intervening portions curved as shown, outer shroud rings 23 and 24 curved to conform to the rings 2| and 22, and circurnferentially spaced, Y-shaped blades 25 which are bridged between the shroud rings 2| and 23 and 22 and 24, respectively, throughout the radial extent of the rings 2| and 22 and between the shroud rings 23 and 24 outwardly of the rings 2| and 22.

The inner periphery of the ring 23 is extended to form an annular shell 26 which is coaxial with and spaced around the adj aoent end of the shaft l4 to thereby form one eye 21 of the pump. Similarly, the inner periphery of the shroud ring 24 is extended in the opposite direction to form a like annular shell 28 that is spaced from the shaft I4, including the seal assembly I9, to form the other eye 29. The impeller is therefore of the double suction type which is self -balanced against end thrusts. As is well understood in the art, liquid entering through the inlet I I divides around the chamber I3 and flows through the eyes 2'] and 29, or low pressure side of the pump, into the plurality of passages included between the shroud rings and blades where it is forced outwardly and discharged into the chamber I3 between the outer peripheries of the rings 23 and 24, or high pressure side of the pump.

Since the periphery of the impeller I8 must have free working clearance with reference to the inner boundary of the volute chamber I3, defined by the annular bores 30 and 3| which are axially spaced to provide an annular opening to the chamber, some of the liquid issuing from the high pressure side of the impeller would flow externally of the impeller directly to the low pressure side, thus lowering the efficiency of the pump. The invention is concerned with substantially preventing this action by means which also render the impeller assembly capable of being bodily inserted in and withdrawn from operating relation to the chamber I3.

A closure ring 32 includes an outer peripheral and annular flange 33 which has press fit rela tion to the bore 33 and an inner peripheral and annular flange 34 which surrounds the shell 26 and is slightly spaced therefrom, the intervening portion of the ring 32 being spaced from the shroud ring 23. A second closure ring 35, generally similar to the ring 32, is provided with outer and inner, annular flanges 33 and 31, respectively, the former having an easy fit relation with the bore SI and the latter surrounding and being spaced from the shell 29. The fit of the flange 35 within the bore 3| may be of the order of .003" to .004.

The flanges 33 and 33 constitute the rim seals of the pump which prevent loss of liquid laterally between the impeller and bores 30 and 3| and the radially outward, pumping action of the ex- 3 ternal surfaces of the shroud rings 23 and 24 with respect to liquid between the closure and shroud rings combats to a substantial extent the tendency of the liquid to flow from the high to the low pressure side between the closure and shroud rings. This action is facilitated by the general similarity in conformation of the closure and shroud rings and their spacing from each other to define outwardly extending channels of shallow depth, all as shown in the drawing. Leakage losses are accordingly reduced to a minimum with a corresponding increase in efflciency.

The flange 36 rests on and may be secured to an annular flange 38 provided on one end of a frustoconical carrier 39 Whose opposite end is similarly flanged at 46 and press fitted or secured to an annular shoulder 4| formed on the bracket i 5. The portion of the carrier 39 between its flanges is provided with a plurality of circumferentially spaced apertures 42 through which the liquid flows to the pump eye 29.

With the above arrangement, incoming liquid flows with equal facility to both eyes of the pump and since the diameter of the rim seal to the left of the impeller is not less than the impeller diameter, being in fact slightly greater in the design shown, it is possible to remove the nuts from the studs it and separate the bracket from the casing, along with the shaft It and the associated assembly, including the impeller E 1 closure ring and carrier 39. The casing iii may therefore be cast in one piece and the warm plete pump is then characterized by the advantages set forth above.

I claim:

1. A centrifugal pump comprising a casing having a side opening and a volute chamber provided with an axial bore and including an annular opening connecting the chamber and bore,

a member closing the side opening and having an annular shoulder, a shaft journaled in the member in coaxial relation to the bore, an impeller including peripheral ioutlets keyed to the shaft and having an outer shroud ring whose radially inward portion is extended to provide an annular shell surrounding and spaced from the shaft to define the axial eye of the pump, the peripheral outlets of the impeller being operably related to the annular opening, a closure ring spaced from the shroud ring and having annular outer and inner flanges, the outer :fiange fitting the bore to provide a rim seal for the impeller and the inner flange encircling the shell in spaced relation thereto, and a perforated, annular carrier supported on the shoulder and having support relation to the outer flange of the closure ring, the peripheral diameter of the outer flange being not less than that of the impeller.

2. A centrifugal pump comprising a casing having a side opening and a volute chamber pro vided with an axial bore and including an annular opening connecting the chamber and bore, a member closing the side opening and having an annular shoulder, a shaft journaled in the member in coaxial relation to the bore, an impeller including peripheral outlets keyed to the shaft and having spaced shroud rings whose radially inward portions are oppositely extended to provide annular shells surrounding and spaced from the shaft to thereby form a pair of axial eyes, the peripheral outlets of the impeller being operably related to the annular opening, a closure ring spaced axially from each shroud ring and having annular outer and. inner flanges, the

outer flanges fitting the bore to provide rim seals on opposite sides of the impeller and each inner flange encircling the shell of the adjacent shroud ring in spaced relation thereto, and a perforated, annular carrier supported on the shoulder and having support relation to the outer flange of the adjacent closure ring, the peripheral diameter of the last named flange being not less than that of the impeller.

3. A centrifugal pump comprising a casing having a side opening and a volute chamber provided with an axial bore and including an annular opening connecting the chamber and bore, a member closing the side opening and having an annular shoulder, a shaft journaled in the member in coaxial relation to the bore, an impeller including peripheral outlets keyed to the shaft and having an outer shroud ring whose radially inward portion is spaced from the shaft to define the eye of the pump, the peripheral outlets of the impeller being operably related to the annular opening, a closure ring spaced from the shroud ring and having an annular outer flange, the-outer flange fitting the bore to provide a rim seal for the impeller and the radially inward portion of the closure ring encircling the inward portion of the shroud ring in spaced relation thereto, and a perforated, annular carrier supported on the shoulder and having support relation to the outer flange of the closure ring, the peripheral diameter of the outer flange being not less than that of the impeller.

4. A centrifugal pump comprising a casing having a side opening and a volute chamber provided with an axial bore and including an annular opening connecting the chamber and bore, a member closing the side opening and having an annular shoulder, a shaft journaled the member in coaxial relation to the bore, an impeller including peripheral outlets keyed to the shaft and having spaced shroud rings whose radially inward portions are spaced from the shaft to thereby form the eyes of the pump, the peripheral outlets of the impeller being cperably related to the annular opening, a closure ring spaced axially from each shroud ring and having an annular outer flange, the outer flanges fitting the bore to provide rim seals on opposite sides of the impeller and the radially inward portion of each closure ring encircling the inward portion of the adjacent shroud ring in spaced relation thereto, and a perforated, annular carrier supported on the shoulder and having support reiation to the outer flange of the adjacent closure ring, the peripheral diameter of the last named flange being not less than that of the impeller.

A centrifugal pump comprising a casing having a side opening and a volute chamber provided with an axial bore and including an annular opening connecting the chamber and bore, a member closing the side opening and having an annular shoulder, a shaft journaled in the member in coaxial relation to the bore, an impeller including peripheral outlets keyed to the shaft and having an outer shroud ring whose radially inward portion is spaced from the shaft to define the eye of the pump, the peripheral outlets of the impeller being operably related to the annular opening, a closure ring spaced from and generally conforming to the shape of the shroud ring to define therewith a shallow, annular channel whose outer end communicates with the annular opening, the closure ring having an annular outer flange fitting the bore to provide a rim seal for the impeller and the" radially inward portion of the closure ring encircling the inward portion of the shroud ring in spaced relation thereto, and a perforated, annular carrier supported on the shoulder and having support relation to the outer flange of the closure ring, the peripheral diameter of the outer flange being not less than that of the impeller.

6. A centrifugal pump comprising a casing having a side opening and a volute chamber provided with an axial bore and including an annular opening connecting the chamber and bore, a member closing the side opening and having an annular shoulder, a shaft journaled in the member in coaxial relation to the bore, an impeller including peripheral outlets keyed to the shaft and having spaced shroud rings whose radially inward portions are spaced from the shaft to thereby form the eyes of the pump, the peripheral outlets of the impeller being operably related to the annular opening, a closure ring spaced axially from each shroud ring and having an annular outer flange, each closure ring generally conforming to the shape of the adjacent shroud ring and defining therewith a shallow, annular channel whose outer end communicates with the annular opening, the outer flanges fitting the bore to provide rim seals on opposite sides of the impeller and the radially inward portion of each closure ring encircling the inward portion of the adjacent shroud ring in spaced relation thereto, and a perforated, annular carrier supported on the shoulder and having support relation to the outer flange of the adjacent closure ring, the peripheral diameter of the last named flange being not less than that of the impeller.

7. A centrifugal pump comprising a casing having a side opening and a volute chamber provided with an axial bore and including an annular opening connecting the chamber and bore, a member closing the side opening and having shoulder means, a shaft extending through the member in coaxial relation to the bore, an impeller including peripheral outlets keyed to the shaft and having an outer shroud ring Whose radially inward portion is spaced from the shaft to define the eye of the pump, the peripheral outlets of the impeller being operably related to the annular opening, a closure ring spaced from the shroud ring and having an annular outer flange, the outer flange fitting the bore to provide a rim seal for the impeller and the radially inward portion of the closure ring encircling the inward portion of the shroud ring in spaced relation thereto, and carrier means supported on the shoulder means and having support relation to the outer flange of the closure ring, the carrier means being arranged to provide for fluid flow to the eye and the peripheral diameter of the outer flange being not less than that of the impeller.

8. A centrifugal pump comprising a casing having a side opening and a volute chamber provided with an axial bore and including an annular opening connecting the chamber and bore, a member closing the side opening and having shoulder means, a shaft extending through the member in coaxial relation to the bore, an impeller including peripheral outlets keyed to the shaft and having spaced shroud rings whose radially inward portions are spaced from the shaft to thereby form the eyes of the pump, the peripheral outlets of the impeller being operably related to the annular opening, a closure ring spaced axially from each shroud ring and having an annular outer flange, the outer flanges fitting the bore to provide rim seals on opposite sides of the impeller and the radially inward portion of each closure ring encircling the inward portion of the adjacent shroud ring in spaced relation, and carrier means supported on the'shoulder means and having support relation to the outer flange of the adjacent closure ring, the carrier means being arranged to provide for fluid flow to the adjacent eye and the peripheral diameterof the last named flange being not less than that of the impeller.

HAROLD A. LOCKHART.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 678,223 Christian July 9, 1901 1,146,079 Krogh July 13, 1915 1,334,461 Kerr Mar. 23, 1920 2,207,208 Thursh July 9, 1940 2,427,307 Schleyer Sept. 9, 1947 2,461,835 Murphy Feb. 15, 1949 FOREIGN PATENTS Number Country Date 33,042 Sweden Apr. 9, 1910 

